Cytomegalovirus (CMV) is the leading infectious cause of birth defects in the United States, and infection of neonates and immunosuppressed individual's results in significant morbidity and mortality. One important step in the genesis of CMV disease is dissemination of the virus from an initial site of replication to distal organs, where new infections are seeded. Mouse CMV encodes a CC chemokine-like polypeptide, termed MCK-2 that is required for peak blood viremia as well as maximal edema and leukocyte infiltration at the initial site of infection. The mechanisms through which MCK-2 mediates this activity are not known. We have produced and purified recombinant baculovirus expressed MCK-2 (rMCK2) for use in studies of MCK-2 function and determination of the cell types MCK-2 acts on. The capacity of rMCK2 to stimulate leukocyte transmigration will be studied in vitro in Boyden chamber assays and the potential for intracellular Calcium flux will be measured spectrophotometrically. In vivo, the cell types recruited by MCK-2 will be determined by flow cytometric analysis of cells isolated from recombinant MCK-2 treated tissue, providing insight into the mechanisms of mouse CMV pathogenesis. [unreadable] [unreadable]